Hi Aine,
You’re right, there is a lot to consider when placing a bet on Betfair Exchange!
Personally I would take the view that it all depends on your profit as calculated in the Price Matcher. For example, if you were trying to lock in a profit at 2.8 on Betfair, you might still be able to profit all the way up to 2.9. So there’s plenty of room to work with.
It might be annoying moving your price from 2.8 to 2.84 and getting less profit, but not laying off and losing the full bet with the bookmaker is far worse. That’s the one thing we need to avoid.
If there was lots of time until the event, I wouldn’t be in a panic to lay off but I would definitely keep an eye on the price and make a decision reasonably early. You don’t want it drifting and then suddenly you’re making a loss.